Steam and gas power generating plant



April 12, 1949. E MERGER T A 2,466,723

STEAM AND GAS POWER GENERATING PL NT Filed April 28, 1945 6/95 [Ne/N65 f (WM/56515110,? mV/U HQ/e com/warez: 7 5

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i i I Am 49 A m l J la? r durum K (3 5 I T Z l P 1: f g9 EmsrMereievand MarcelEhlin r BE l/PIVENTORS Patented Apr. 12, 1949 STEAM AND GAS rowan GENERATING PLANT Ernest Mercier and Marcel Ehlinger, Paris,

France, assignors to Societe Civile dEtudes Thermo-Mecaniques, Marseille, France Application April 28, 1945, Serial No. 590,919 In France October 1-6, 1942 Section. 1, Public Law 690, August 8, 1946 Patent expires October 16,1962

8 Claims;

Inthe production of power there is employed either a single fluid flow in internal combustion engines, or two fluids flowing. in parallel paths while effecting heat exchange with each other, such as the burnt gases andthe steam in a boiler, or a greater number of fi'uids, for instance in. the. combined steam and mercury vapor engines.

Considering, the particular case of apparatus in which two or more fluids are employed, the.

methods presently used rely generally upon the use. ofivapor generatorswhich are fed with combustiongas at normal atmospheric pressure. Precompressed combustion air'hasbeen resorted to insome. particular instances, but such a preparatory compression was limited to a few kilograms. per square centimeter, and such arrangements are provided merely with a viewto imparting a. high speed to the burnt gases. I

Essentially, this invention provides a system of power. generation employing two or more fluids all of" which are brought simultaneously to high pressures and temperatures in such manner that the fluids that effect heat exchanges with each other shall have the same or not much diiferent pressures and that on the other hand both shall be able of themselves, by their expansion, to generate a substantial. portion. of" the power; Ordinarily one of those fluids functions onlyas a passive heat vehicle, for example the combustion gases in-v conventional boilers. In some. particular instances itis contemplated, according to this invention, to bring the air and the combustion gas developed therefrom to a substantially higher pressure than the steam pressure in order to improve the heat exchange coefficients. In all these processes practically every irreversible transformation, such as wire drawing and friction, is to be carefully avoided.

Considering for example the simple instance where only two fluids follow parallel paths, this invention contemplates the use of a. steam boiler operating, e. g., at a pressure higher. than 100 kg./.cm."and' in which the combustion air and the burnt gases themselves are likewise brought to a high pressure above 100 kg/cmfi.

In this simple case the path of the combustion air may comprise cascade air-compressors combined with heat-exchangers suitably arranged between. thesuccessive pressure stages with a view tobringing the combustion air, e. g., to a pressurcof 120 kgJcm; and a temperature of 400 C.. at: its entrance into thev combustion chamber ofithcsboiler; then to the combustion chamber of the boiler through which the" gases flow" while' 2 taking up the heatyielded by'the fuel and transieferring the same to the steam but withoutany" substantial decrease in the pressure ofithe burnt ases.

At the outlet of the boiler: the h'ot'gases are still substantially at the' same pressure and at" a temperature of 550 to 600 C. or higher, de pending, on the heat resisting'propertiesof the metals used in construction. After passing from the combustion chamber said gases arefedin parallel or in cascade into a gas turbine andthe: above mentioned air compressors. The combina tion motor-compressor units may advantageously be designed as free-piston units in consideration of the high efficiency of such machines. The gas turbine can be dispensed with in some appli cations.

Finally, the gases are discharged into the atmosphere at a temperature only slightly higher than that of the ambient air or, atall' events'at'a substantially lower temperature than Ci, which makes it possible to recover the thermal units of the fuel which were necessary for heating up and vaporizing the water contained in the fuel, both in the form of water of constitution,

i. e., chemically combined water; and" as free-= water or moisture.

In its turn, the circuit of the water and steam is as follows:

At the outlet of the steam turbine condenser the water is directed into the'series of heat-exchangers above mentioned; the purpose ofwhich is to lower the temperature of the air undergoing compression and to decrease the amount of power" necessary for the compression of such air. The water, if desired, may also pass into the-jacket" of the high pressure motor of the motor-compres*- sor groups and finally into one or several: re-

heaters operating on steam tapped" from'. the:

turbine. The water thus re-heated' isa-fed into the main boiler, flows as steam through the high pressure stages of the turbine, then-through a steam reheating or re-superheating unit or. unitsand finally through thelow pressurestagea oi? cording to the invention utilizing two fluids for power generation.

Fig. 2 shows diagrammatically a system utilizing three fluids.

In these figures l, 2, 3 and 4 designate the air compressors arranged in cascade, that is, with the air compressed in the low pressure unit delivered to the next unit for compression to a higher pressure,

5. 5 and 1 are the intermediate coolers for the air being compressed,

8 is the main boiler,

9 is the gas outlet pipe leading from the boiler,

10 is the gas turbine,

H is the pipe carrying the gases discharged under pressure from the boilers into the motors of the compressor units,

l2, l3, l4 and I5 are the motors of the compressor units in the order of reducing pressure,

I6 is a compressed air branch pipe tapped from the second stage of compression and supplying air to the reheater or resuperheater l1.

I8 is the gas exhaust pipe leading from the resuperheater,

i9 is an additional supply pipe leading gas from the reheater into the gas turbine at a suitable stage thereof,

is the pipe through which a portion of the gases issuing from the resuperheater flows to the motor M of the second-stage compressor and thence into that of the first stage compressor l5 in cascade therewith,

2| is the condensed water pipe leading from the'steam turbine condenser 10 to the heat exchanger 5 for cooling the air between the first and second stages of compression,

22 is the pipe leading the heated water from the coolers 5, 5 and 1 to the reheater 23 which is heated with steam tapped from the steam turbine and arranged to receive and further heat the condensate heated in coolers 5. 6 and l.

24 is a water feed-pipe leading from re-heater 23 to deliver the heated water as feed water tothe boiler 8.

25 is the pipe for delivering high pressure steam from boiler 8 to the high pressure turbine T.

26 is the pipe leading the partially expanded steam from turbine T to the reheater or resuperheater I1.

21 is the pipe carrying reheated or re-superheated steam to the low pressure turbine T.

28 and!!! are the fuel feed pipes leading into the main boiler 3 and the reheater or re-superheater l1 respectively.

T is the high pressure section of the steam turbine, and T the low pressure section of the same.

The above described cycle admits of some modifications; for instance:

1) The steam may be re-superheated repeatedly.

'(2) The heating fluids which are still under pressure may undergo one or several re-superheatings for which additional combustion may be used, the pressure and temperature being so selected that the gases as they flow out of the expansion machine or machines, e. g. the gas turbine, shall be at thepressure and substantially at the temperature of the atmosphere.

(3) The combustion air may be heated up after its-compression by heat derived from the heated fluids, whether partially expanded or not, and this, may be done one or several times.

(4) The system may be operated with two dii ferent heated fluids (such as water and mercury) instead of only one (steam in the preceding example), one of said fluids then acting as the cooling medium for the other.

(5) The heating system may be provided by the incompletely burnt gases escaping from a supercharged Diesel motor cylinder or from a free-piston or like hot gas generator. In such a case ordinary or free-piston Diesel compressors replace all or part of the above mentioned motorcompressor units. The gases from the Diesel motors or from the generators may or may not undergo a complementary compression before their use, with or without a combined cooling.

Fig. 2 is derived from Fig. 1 by the incorporation therein of the complementary devices enumerated above.

30 and 3! in said figure designate the compressors for the air and contingently the fuel gas, two such compressors only being shown in order to simplify the drawing.

32 is the boiler which comprises a steam generating section 33, a mercury vapour generating section 34 and the heat transfer elements of two re-superheaters 35 and 36.

3! is the steam turbine,

38 is the mercury vapour turbine,

39 is a pump which forces the condensate into the intermediate air cooler 40,

4| is a complementary cooler cooled by an additional cooling medium,

42 is the pipe delivering the condensate after being heated in air cooler to the heaters 43 and 44 which are heated by steam tapped from certain stages of the steam turbine,

45 is an exchanger in which the heat of the mercury vapor in condensing is transferred to the condensed water, the condensate, from the steam turbine, both to the condensate from the main condenser I0 and from the heaters 43 and 44,

46 is the water feed pipe leading to boiler 32 from the heat exchanger 45.

41 is the mercury pump which feeds the mercury condensate from the condenser 45 to the mercury boiler through pipe 48,

49 is the mercury vapour pipe leading to the mercury Vapour turbine 38,

50 is a pipe leading to the mercury boiler 34 through the heat exchanger 52 in which the mercury vapour, from mercury vapour turbine 38 heats up the combustion air for boiler 32,

53 is the gas exhaust pipe leading from the combustion gas space of the boiler 32 through the pipe 54 into the compressor motors 55 and 56 while the gases also are conveyed through pipe 12 into the gas turbine 14 in connection with which a separate reheater or re-superheater 51 may be provided,

58 and 59 are the fuel feed pipes leading respectively to burners in the combustion space of the main boiler 32 and of the reheater or resuperheater 51.

BI] and SI are reservoirs for the compressed air to serve as equalizers for the air-circuit and contingently as an aid for peak loads.

What we claim as our invention and desire to secure by Letters Patent is:

1. Power generating plant comprising a steam boiler for generating therein high pressure steam, means providing a combustion chamber for combustion of fuel therein at a pressure of the degree of thepressure of the generated steam to, generate steam in said boiler, a steam turbine, means for delivering the steam generated in said steamgrooms boiler to a high pressure 'fs'tage of said steam turbine, laireheater, means .for feeding steam from a stage of said turbine to said reheater for reheating said steam therein, means for heating said reheaterwith-combustion gases at "a temperature-sufficient to effect said reheating of said steam and 'at a pressure vof the degree of the pressure of the steam delivered to said'reheater, agasturbine, means for delivering to said-gas turbine atleast a portion of the combustion gases from said combustion chamber and at least a portion of said're'heater combustion gases after heating'said steam from said-turbine for developing power from said gases in said gas turbine, argas-engine driven compressor unit, and means tor -delivering to the gas engine of said unit at least arportion of said gasesfrom said combustion chamber and at least a portion of said reheater combustion gases for driving said compressor unit.

2. Power generating plant comprising a steam boiler for generating therein high-pressure steam, means providing a combustion chamber for the combustion of fuel therein to generate steam in said boiler, means for feeding the combustion air to said chamber to effect combustion therein substantially at the pressure of the generated steam, a steam turbine, means for delivering the steam generated in said steam boiler to a high pressure stage of said steam turbine, a reheater heated by combustion gases, means for feeding steam from a stage of said turbine to said reheater for reheating said steam therein, means for delivering the steam after reheating to a low pressure stage of the turbine, a gas turbine, means for delivering to said gas turbine a portion of the combustion gases from said reheater, a gas engine-compressor unit, and means for delivering to the engine of said unit another portion of said combustion gases from said reheater for driving said engine.

3. Power generating plant comprising a steam boiler for generating therein high pressure steam, means providing a combustion chamber for the combustion of fuel therein to generate steam in said boiler, means for feeding the combustion air to said chamber to effect combustion therein substantially at the pressure of the generated steam, a steam turbine, means for delivering the steam generated in said steam boiler to a high pressure stage of said steam turbine, a reheater heated by combustion gases, means for feeding steam from a stage of said turbine to said reheater for reheating said steam therein, means for delivering the steam after reheating to a low pressure stage of the turbine, a gas turbine, means for delivery to said gas turbine a portion of the combustion gases from said reheater, a gas engine-compressor unit, means for delivering to the engine of said unit another portion of said combustion gases from said reheater for driving said engine, a condenser for condensing steam discharged from said steam turbine, and means for cooling the air compressed in said compressor unit by heat exchange with the condensed water from said condenser.

4. Power generating plant as defined in claim 1 which comprises a mercury vapor turbine, a mercury vapor generator heated by the combustion gases of said combustion chamber to generate the mercury vapor, means for delivering the generated mercury vapor to said mercury vapor turbine for developing power therein, a condenser connected to said steam turbine for condensing the expanded steam discharged therefrom, and a heat exchanger connected to said mercury vapor turbine to receive therefrom the expanded mer- 6 cury vapor an-d connected to said-rcondenser 'tto receive therefrom the condensate zof thexsteam for heating said condensate concomitantlywith cooling of the mercury vapor.

5. Power generating plant comprising *a stea'm boiler for generating therein high-pressure steam, means providing a-combustion chamber for combustion of .fuel therein "at a pressure of the degree of the-pressure-of the generated steam togenerate steam in said boiler, a steam turbine, means for delivering the steam generated in said steam boiler to #a high pressure stage of said steam turbine, a reheater, means for feeding steam -'-'from a stageofsaid turbineto said reheater for reheating said steam therein, means for heating said reheater with combustion gases at a temperature sufficient to effect said reheating of said steam and at a pressure of the degree of the pressure of the steam delivered to said reheater, a gas turbine, and means for delivering to said gas turbine at least a portion of the combustion gases from said combustion chamber and at least a portion of said reheater combustion gases after heating said steam from said turbine for developing power from said gases in said gas turbine.

6. Power generating plant comprising a steam boiler for generating therein high pressure steam, means providing a combustion chamber for combustion of fuel therein at a pressure of the degree of the pressure of the generated steam in said boiler, a steam turbine, means for delivering the steam generated in said steam boiler to a high pressure stage of said steam turbine, a reheater, means for feeding steam from a stage of said turbine to said reheater for reheating said steam therein, means for heating said reheater with combustion gases at a temperature suificient to effect said reheating of said steam and at a pressure of the degree of the pressure of the steam delivered to said reheater, a gas engine driven compressor unit, and means for delivering to the gas engine of said unit at least a portion of said gases from said combustion chamber and at least a portion of said reheater combustion gases for driving said compressor unit.

'7. Power generating plant comprising a steam boiler for generating therein high pressure steam, means providing a combustion chamber for combustion of fuel therein at a pressure of the degree of the pressure of the generated steam to generate steam in said boiler, a steam turbine, means for delivering the steam generated in said steam boiler to a high pressure stage of said steam turbine, a reheater, means for feeding steam from a stage of said turbine to said reheater for reheating said steam therein, means for heating said reheater with combustion gases at a temperature sufficient to effect said reheating of said steam and at a pressure of the degree of the pressure of the steam delivered to said reheater, a gas turbine, means for delivering to the high pressure stages of said gas turbine combustion gas from said combustion chamber, a multiple expansion gas engine, and means for delivering to a low pressure stage of said gas engine combustion gases from said reheater.

8. Power generating plant comprising a steam boiler for generating therein high pressure steam, means providing a combustion chamber for combustion of fuel therein at a pressure of the degree of the pressure of the generated steam to generate steam in said boiler, a steam turbine, means for delivering the steam generated in said steam boiler to a high pressure stage of said steam turbine, a reheater, means for feeding steam from a stage of said turbine to said reheater for reheating said steam therein, means for heating said reheater with combustion gases at a temperature sufiicient to efiect said reheating of said steam and at a pressure of the degree of the pressure of the steam delivered to said reheater, a gas turbine, means for delivering to the low pressure stage of said gas turbine combustion gases from said reheater to develop power in said gas turbine, a multiple expansion gas engine, and means for delivering to a high pressure stage of said gas engine combustion gases from said combustion chamber.

ERNEST MERCIER.

MARCEL EHLINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

